Worldwide, ants are a powerful ecological force, and they appear to be dominant components of animal communities of many tropical an temperate ecosystems in terms of biomass and numbers of individuals. However, the biotas of many Pacific islands evolved without ants. Relatively few ant species have been successful invaders of native communities on continents, and these include most of the species that pose the greatest problems for Pacific islands. They generally have multiple queens per colony, are unicolonial (lacking internest aggression), quickly recruit to food items, thrive in a variety of habitats including disturbed areas, and can be highly aggressive to other any species. Virtually nothing has been published on effects of non-native ants on native arthropod fauna on Pacific islands with the exception of Hawaii, the Galapagos archipelago, and New Caledonia. In addition, many ant species in the Pacific have long been a nuisance for humans, and significant agricultural impacts have occurred from ants tending hemipteran insects of crop plants.